Quantum trails and memory effects in the phase space of chaotic quantum systems

Fuente: arXiv
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Main Author: Pizzi, Andrea
Format: Preprint
Published: 2024
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author Pizzi, Andrea
author_facet Pizzi, Andrea
contents The eigenstates of a chaotic system can be enhanced along underlying unstable periodic orbits in so-called quantum scars, making it more likely for a particle launched along one such orbits to be found still there at long times. Unstable periodic orbits are, however, a negligible part of the phase space, and a question arises regarding the structure of the wave function elsewhere. Here, we address this question and show that a weakly-dispersing dynamics of a localized wave packet in phase space leaves a "quantum trail" on the eigenstates, that is, makes them vary slowly when moving along trajectories in phase space, even if not periodic. The quantum trails underpin a remarkable dynamical effect: for a system initialized in a localized wave packet, the long-time phase-space distribution is enhanced along the short-time trajectory, which can result in ergodicity breaking. We provide the general intuition for these effects and prove them in the stadium billiard, for which an unwarping procedure allows us to visualize the phase space on the two-dimensional space of the page.
format Preprint
id arxiv_https___arxiv_org_abs_2412_04310
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quantum trails and memory effects in the phase space of chaotic quantum systems
Pizzi, Andrea
Quantum Physics
Statistical Mechanics
Chaotic Dynamics
The eigenstates of a chaotic system can be enhanced along underlying unstable periodic orbits in so-called quantum scars, making it more likely for a particle launched along one such orbits to be found still there at long times. Unstable periodic orbits are, however, a negligible part of the phase space, and a question arises regarding the structure of the wave function elsewhere. Here, we address this question and show that a weakly-dispersing dynamics of a localized wave packet in phase space leaves a "quantum trail" on the eigenstates, that is, makes them vary slowly when moving along trajectories in phase space, even if not periodic. The quantum trails underpin a remarkable dynamical effect: for a system initialized in a localized wave packet, the long-time phase-space distribution is enhanced along the short-time trajectory, which can result in ergodicity breaking. We provide the general intuition for these effects and prove them in the stadium billiard, for which an unwarping procedure allows us to visualize the phase space on the two-dimensional space of the page.
title Quantum trails and memory effects in the phase space of chaotic quantum systems
topic Quantum Physics
Statistical Mechanics
Chaotic Dynamics
url https://arxiv.org/abs/2412.04310